1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly to a transflective liquid crystal display device which incorporates a retardation film in a color filter substrate side.
2. Description of the Related Art
For example, as described in patent document 1 (JP-A-2005-338256), a transflective liquid crystal display device which includes a transmissive portion and a reflective portion in the inside of one sub pixel is used as a display for a portable equipment.
FIG. 13 is a cross-sectional view showing the cross-sectional structure of an essential part of one sub pixel in one example of a conventional transflective liquid crystal display device. FIG. 13 is also a cross-sectional view illustrated as FIG. 2 in the above-mentioned patent document 1.
In FIG. 13, numeral 10 indicates a liquid crystal layer, numeral 21 indicates scanning lines, numeral 23 indicates common lines, numeral 28 indicates pixel electrodes, numeral 29 indicates counter electrodes (also referred to as common electrodes), numerals 31, 32 indicate glass substrates, numeral 33 indicates a first orientation film, numeral 34 indicates a second orientation film, numeral 35 indicates a third orientation film, numeral 36 indicates color filters, numeral 37 indicates a leveling film, numeral 38 indicates an incorporated phase plate, numeral 41 indicates a first polarizer, numeral 42 indicates a second polarizer, numeral 43 indicates a light diffusion layer, numeral 51 indicates a first insulation film, numeral 52 indicates a second insulation film, numeral 53 indicates a third insulation film, numeral 61 indicates a transmitting light, and numeral 62 indicates a reflection light.
The common lines 23 are configured to project into the inside of the pixel electrode 28 at a portion where the common lines 23 intersect the pixel electrodes 28, and the common lines 23 reflects light as indicated by the reflection light 62 in FIG. 2.
In FIG. 13, portions where the common lines 23 is overlapped to the pixel electrodes 28 constitute reflective portions 131, and overlapped portions of the pixel electrodes 28 and the common electrodes 29 other than the reflective portions 131 constitute transmissive portions 130 which transmit light from a backlight therethrough as indicated by a transmitting light 61 in FIG. 2.
In the transflective liquid crystal display device shown in FIG. 13, a main surface side of a glass substrate (SUB2) constitutes an observation side.
In the conventional transflective liquid crystal display device shown in FIG. 13, the pixel electrodes 28 and the planar counter electrode 29 are stacked by way of an interlayer insulation film 53, and arcuate electric lines of force which are formed between the pixel electrodes 28 and the counter electrodes 29 are distributed in a state such that the electric lines of force penetrate the liquid crystal layer 10 and hence, the orientation of the liquid crystal layer 10 is changed.
A length of a cell gap of the reflective portion 131 is set to an approximately half of a length of a cell gap of the transmissive portion 130. This is because that the light passes the liquid crystal layer 10 twice due to reciprocation in the reflective portion 131 and hence, an optical path length of the transmissive portion 130 and an optical path length of the reflective portion 131 are made to substantially agree with each other.
In the transmissive portion 130, the contrast of light is displayed by making use of the e birefringence of the liquid crystal layer 10, while in the reflective portion 131, the contrast of light is displayed by making use of the birefringence of the incorporated phase plate 38 which is arranged inside a liquid crystal display panel and the liquid crystal layer 10.
Here, as a prior art document related to the present invention, JP-A-2005-338256 is named.